State government bans on gas connections to new premises have caused confusion among their respective constituents, and outrage among stakeholders.

Credit to Premier Chris Minns and the New South Wales government for wisely avoiding this decision, however some local councils have bypassed state law, banning gas through their development control plans (DCPs) on the questionable grounds of health risks and economic benefit.

This move evades what was initially dismissed by many as unlawful under NSW SEPP: Clause 2.2, which prohibits such bans if the aim is reducing emissions. Being made aware of a legal loophole, a group of local councillors (who have no known expertise, or knowledge of the gas industry) proposed motions to ban gas based on health dangers and economic benefits of electrifying your home.

The City of Sydney council passed a motion to ban gas last year, based on speculative and patently false claims, such as gas cooktops being ‘associated with around 12 per cent of childhood asthma in Australia’, and a promise that people would ‘save $924 a year on their bills if they switched gas appliances to electric ones’. The council also commissioned a supporting analysis, which falsely cited a study claiming ‘a child living with a gas stove faces a similar asthma risk to a child exposed to second-hand cigarette smoke’. Read the study, however, and this claim is nowhere to be found.

This demonisation of gas explains the recent surge in the promotion of a better form of energy. Nuclear power, you ask? Don’t be silly, you old fossil… It’s the next best thing (after nuclear power, coal, crude oil, natural gas, LPG, ethanol, and petroleum of course). It’s ‘renewable’ gas.

But what are renewable gases? Are they energy-dense, producible at scale, efficient, and reliable? What infrastructure is required for their uptake? How expensive are they to produce? If you look closely enough, the shiny exterior wears off quickly.

Both renewable gases, hydrogen and biomethane, are less energy-dense than their existing counterparts: natural gas and LPG. Many proponents of hydrogen will correctly point out that hydrogen has a higher energy content than other gases, but this is often misrepresented or misunderstood. Hydrogen has a higher energy content by mass, not by volume. Comparing by volume, approximately twice as much biomethane and three times as much hydrogen must be burned to produce the same amount of energy as natural gas.

Hydrogen gas production requires two main ingredients: (a) A lot of water and (b) More electricity energy input, than hydrogen energy output.

The NSW government’s hydrogen strategy estimates 9L required water per 1kg hydrogen gas. But it is purified water that is required, not regular water which can damage electrolysers and decrease their efficiency. Purified water requires about 2L water per 1L. This brings our water requirement to roughly 18L per kg of hydrogen, not accounting for wastage and loss.

Existing electrolyser technology operates at efficiencies close to 75 per cent (with electricity requirements of 52.5 kWh/kg hydrogen produced). Using kWh/kg conversion rates, 1kg of hydrogen can produce 39.4 kWh energy. Therefore, the energy trade-off looks like this:

52.5kWh electricity INPUT = 39.4 kWh hydrogen energy OUTPUT

According to the same hydrogen strategy, green hydrogen (the ‘clean’ type of hydrogen) costs AUD 0.72 per m3 to produce, with electricity making up around 60-70 per cent of overall cost. This may be seen as a cheap production cost, however, hydrogen’s poor energy density must be considered. The path to lowering this production cost literally hinges on a rapid downward trend of renewable energy costs – a trajectory that, under the current government’s energy policies and renewable energy rollout seems like wishful thinking.

But why would we force constituents to use a poor form of energy that is expensive to produce and requires more electricity input than what your will receive in return? There you go again with the nosy questions, you silly old fossil.

The production of biogas also requires two ingredients: (a) Organic matter (namely human sewage) and (b) electricity.

There is no shortage of human sewage, with households producing roughly 200-300L wastewater per person per day. One positive in biogas is the fact that a by-product of human waste is used as the fuel source, as opposed to using precious water. This by-product would otherwise need to be dealt with through a treatment process but is instead used to generate a useful energy source. Existing technology for the extraction of biomethane from raw biogas has varying electricity requirements, depending on the manufacturer and scope of the project. Using the first-of-its-kind Sydney Water/Jemena biomethane injection plant, electricity requirements come in at 0.26kWh/kg biogas produced. The biogas energy trade-off looks like this:

0.26kWh electricity INPUT = 6kWh biogas energy OUTPUT

This is a much higher energy yield than hydrogen, however, the poor energy density compared with natural gas still must be remembered, albeit with the benefit of recycling sewage by-products.

Both renewable gases have stark differences regarding infrastructure requirements.

Once Biomethane has been extracted from raw biogas, no further changes are required to inject it into the natural gas network. Biogas is ‘completely compatible with existing gas appliances and can be used in those manufacturing processes which currently rely on gas for heat’.

Currently, Australia’s existing gas pipelines are unsuitable for transmitting 100 per cent hydrogen gas. This is because hydrogen’s chemical properties affect the material properties of steel pipework, an effect known as ‘hydrogen embrittlement’. There is optimism that existing pipelines can be upgraded for hydrogen transmission, but this has only been confirmed in theory and is yet to be demonstrated. Upgrades to pipe networks still cost less than building new ones, but it incurs a cost nonetheless. Most states are trialling a blend of hydrogen into their natural gas networks and envision a 10 per cent hydrogen blend by 2030. Once again, the lower energy density of hydrogen creates issues. According to AGL, it would take 3.3m3 of hydrogen to match the energy output of 1m3 of natural gas. This creates a headache regarding consumer bills, as it is extremely difficult to calculate what percentage of hydrogen may be in a consumer’s gas supply at any one time. The more hydrogen blended into the system, the poorer the quality of gas supplied to the consumer. According to AEMC:

‘If the heating value is not accurately and frequently measured, the customer could be over billed for the amount of energy delivered.’

(Pictured above) Gas Blends Table, which demonstrates the energy value decrease vs. hydrogen blend increase (AEMC) Source: Policy_Portrait_Layout (aemc.gov.au)

To store hydrogen gas in sufficient quantities, it must be compressed at 700 times normal atmospheric pressure or refrigerated to -253C. This adds transport and transmission costs and raises safety concerns. Storing and handling hydrogen at such a low temperature that can result in cryogenic burns and lung damage. One alternate method of transporting hydrogen is converting it into ammonia (which can be stored at -33C and at normal atmospheric pressure). However, the ammonia must then be converted back to hydrogen. Each conversion, from water to hydrogen to ammonia and back, incurs energy loss.

Renewable gas should be pursued in a cautious manner, mixed with a dose of reality and healthy scepticism. In regard to pursuit and investment in renewable gases, the words of the Public Interest Advocacy Centre ring true: ‘It must not come at the expense of consumers or with added risk to their efficient and affordable access to essential energy.’

We should also ask some hard, but important questions:

• Are there better energy options available?
• Should we progress down the path of renewable gases with such urgency?
• Should we ban new connections of fossil fuel gases (NG and LPG) and mandate the use of renewable gases?
• Or should we let the market innovate, and consumers indicate which gas is more reliable, efficient, and more affordable?
• On what grounds are state governments and local councils imposing bans on gas?
• Are federal, state, and local governments banning gas and pursuing renewables because they care about the environment?
• If so, why does Australia sell most of its mined coal, natural gas, and uranium on the international market? (As of 2023 – Australia exports 93 per cent of its black coal, 79 per cent of its natural gas, and 100 per cent of its uranium.)
• Does environmental concern come second to financial gain? (Australia’s natural gas exports for 2023 came in at around $92 billion, uranium exports at $1.2 billion, and metallurgical coal exports at $62 billion.)
• By mandating renewable energy use domestically, and selling fossil fuels internationally, are we shifting our emissions guilt elsewhere?

Don’t be a silly old fossil, and get with the times.